


See Through

by overdose



Category: Ao no Exorcist | Blue Exorcist
Genre: Half-Sibling Incest, M/M, Masturbation, Voyeurism
Language: English
Status: Completed
Published: 2017-12-10
Updated: 2017-12-10
Packaged: 2019-02-13 00:59:01
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 968
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12972240
Author URL: https://archiveofourown.org/users/overdose/pseuds/overdose
Summary: Oh, how wrong Mephisto is. Behind the closed door is someone listening in to his horror and dismay.





	See Through

**Author's Note:**

> God is judging me from above. We're all going to Hell.

"You shouldn't hide your feelings like that, Rin." Mephisto grinned as he towered over the younger demon, brushing his cheek with a gloved hand. "Look at the situation we're in now." he sighs, looking at Rin with a disappointed face. 

Rin is bright red. He bites his lip and tries to look away from Mephisto, but the older demon holds his chin tightly and chuckles. "Stop that..." Rin whines, unintentionally frowning in a cute way. He didn't want Mephisto to know he wanted this- wanted  _him_ \- but he can't help it. Rin furrows his eyebrows and leans to kiss Mephisto's lips. 

Mephisto is certainly cut off guard. He kisses back, of course, and starts roaming his hands on Rin's body, stopping at Rin's obvious, hard rock erection. Rin squeaked when Mephisto touched it, breaking the kiss. "Is something the matter, my Rin?" Mephisto grins mischievously. "I told you not to hide your feelings~" he said, unzipping Rin's pants. He takes off his gloves and sets them aside, then pulls down Rin's pants.  

"S-Shut up." Rin's breath hitched when Mephisto's cold hands touches his dick. He's so embarrassed by the way Mephisto teased and joked with him, but that's the least of his worries. Mephisto stares at him with a playful smile as he jerks Rin's dick slowly. 

Rin tries his best to quietly moan, biting his lip. His mouth is slightly open, and Mephisto leans in to kiss him in the most sloppy way possible, their tongues sliding against each other. 

"No need to be shy." Mephisto licked his lips when they part, rubbing his thumb on the head of Rin's dick. "We're the only ones in the dorm right now... Sing to your little heart's desire." 

Rin nods slowly. He starts begging for Mephisto to go faster, that he's desperate and can't wait any longer. "Just- Just fuck me already, Mephisto," Rin gasps when the headmaster pulls him to the bed. 

Oh, how wrong Mephisto is. Behind the closed door is someone listening in to his horror and dismay. Yukio gulps, hearing the removal of clothes and the bed creaking. He can't see what's happening, but he can envision it. His brother's flushed face with sweat dripping down his forehead, Mephisto's devilish grin as he fucks into Rin's small, perky ass, nail marks engraved into the younger's soft skin. 

It's so wrong to think like this, but each time he imagines Rin's naked body full of cum, his dick responds delightfully. But Yukio can't seem to gather up the energy and leave them alone. 

"F-Fuck, Mephisto!" Rin cries out, the banging of a wall startles Yukio. "Why are you so big- fuck-" he gasps, unable to catch his breath. 

"Please, Rin, how you flatter me so." Mephisto says, the sound of what Yukio can decipher as lotion or lube fills up the room. "I'm not even fully in, yet." he chuckles. 

Yukio curses mentally, looking at the problem in his pants. Just get up and go to the bathroom, Yukio tells himself. He can't. 

"Oh,  _fuck_ -" Rin whines. "It's big, Mephisto- Don't-" he gasps, then pants as Mephisto thrusts into him slowly. "Y-Yes- yes yes, fuck!" Rin rolls his eyes with bliss as Mephisto picks up his pace, smacking into him. 

"Look at you," Mephisto comes to a stop. "Getting a bit overwhelmed, aren't we?" he leans down and kisses Rin again, biting the younger demon's lip, then sucks on his neck. 

 _Fuck._  Yukio has his pants lowered slightly, as well as his underwear. He starts jerking off his own dick with his eyes closed, imagining what the two are doing. The sounds are more than enough. He finds himself quietly moaning Rin's name when his brother's blissful noises echo in the dorm. Yukio picks up his pace with Mephisto's grunts and thrusts. Just the thought of those two together made him close to releasing. 

"Mephisto, I need to cum!" Rin shouts. In response, Mephisto nods. The younger demon sighs happily as his cum spills out, dripping down his legs and stomach. He steadies his breath. 

"Mm~" Mephisto sighs happily as he pulls out of Rin and goes to sucks on his stomach, licking all his cum up like it was a sweet. "Come here, Rin." he says. 

"Ah!" Rin gasps as Mephisto pulls his head towards his large, thick dick. Rin loved every inch of it. He gasps again when Mephisto grunts, coming all over his face. "Mm-" Rin is about to complain but Mephisto kisses him and laughs. 

 _Fucking shit!_ Yukio clamps a hand over his mouth as he spills all over his hand. He swallows the breath he was holding and slides down the wall, ashamed of what he had done. He wanted more. He wanted to fuck Rin and see that lustful face himself. Yukio gulps, headed to the bathroom. He would leave the dorm and come back later, pretending that never happened. 

"You're disgusting." Rin says, scolding Mephisto as he wipes his face. "Stop kissing me." he mutters quietly, blushing as Mephisto presses his lips all over his cheeks. 

"I can't help it, Rin~ You're so cute." Mephisto smiles. He gets up from the bed and with a snap of his fingers he's all cleaned up like nothing happened. "I'm going to the bathroom to clean you up myself. Stay there for me, will you?"

Rin nods and watches as Mephisto leaves his room, winking at him. 

Mephisto whistles on his way to the bathroom. He knocks on the door with a huge grin on his face. 

Yukio freezes.

"You know, Yukio," Mephisto begins. "If you ever want to join in on the fun, all you have to do is ask." With a chuckle, he adds, "I'm sure Rin wouldn't mind." 

 _...He wouldn't?_ Yukio thinks, biting his lips. The proposal is tempting. 


End file.
